1. Field of Invention
This invention pertains to temporary structures serving as retaining berms or bins for holding hazardous material against escaping. In particular, to prevent oil well drilling mud and other fluids released during drilling operations from escaping the site, and to protect the environment near the tank batteries used for holding drilling fluids, fuel, and supplies. The system may be stored and transported as part of a drilling rig.
2. Description of Prior Art
In environments where the soil may be disturbed, earth is piled up in berms to form a closed area then covered with an impervious sheet of geocloth or similar. Earth berms require heavy equipment to scoop and pile dirt and to push it back into place when the need for the holding pen is over. In environments where the soil cannot be disturbed, is too hard, or is delicate tundra, timbers such as old railroad ties are stacked as a pen and the impervious geocloth secured to the timbers by nailing. The timber berms require heavy equipment to place and remove. Timbers generally are too heavy to handle without machinery and if treated with creosote or other preservatives, they may leach toxic chemicals into the ground where they are placed. This small but significant contamination has to be scooped up and removed for proper disposal. The heavy timbers require larger hauling equipment and more storage space than the invention described herein.
The patent literature shows several portable or temporary holding, berm-like, structures. Most are for special purposes, not suitable for general or arctic use.
U.S. Pat. No. 5,098,220, by Carol Norman, shows a shallow pit lined with an impervious sheeting surrounding an oil well head. The marginal attachment is not shown and the text indicates that there are several methods in use. The railroad ties described above are likely to be one suitable means. Miss Norman's invention is intended for finished wells, and is insufficient for use as protection during the drilling operation.
U.S. Pat. No. 5,236,281, by Dennis Middleton, describes a polyurethane dike device (berm) for use on concrete floors. Sections of the berm or dike are joined by gluing a form-fitting molded splice piece across the interstitial space between adjacent linear sections. The assembly cannot be disassembled without destroying at least part of the components, rendering them not reusable.
U.S. Pat. No. 5,820,297, also by Dennis Middleton, is a similar device. It is foam filled and designed to be glued to a flat floor. Joining is by gluing a splice piece cut from sheet stock over the joint.
U.S. Pat. No. 5,800,091, by Edward Van Romer, is another dike similar to the Middleton invention, except that the supporting structure is pneumatic and the dike is sufficiently pliable to permit a wheeled vehicle to roll over the wall portion.
U.S. Pat. No. 5,520477, by Kevin Fink, uses honeycomb core panels connected by H shaped joiners in cooperation with clips having securing barbs. At first glance the clips resemble the membrane-holding clips of the present invention. However, examination discloses that the barbs are not for holding any third component (membrane) in place. They are intermediaries between the panel edges and the H joining bar. The barbs fit into cooperating grooves or holes in the panel and H bar. The Fink figures clearly show this. In particular, FIGS. 4–12.
The Fink panel joining and corner assemblies have no resemblance to the structures of the present invention.
U.S. Pat. No. 5,857,304, by Stuart Karten, et al, has a key-way cut into the ends of the panels and a key system sliding into the key-ways, thereby joining two panels together. The present invention has no key-ways.
U.S. Pat. No. 5,882,142, by Donald Siglin, et al, is a permanent containment dike comprising panels bolted to posts set into concrete and lined with an impervious sheet of geotextile, which is secured to the upper rim of the wall by bolted clamps. This system requires considerable labor, precision placement of the posts, and does environmental damage. In contrast to the present invention, Siglin bolts the panels at overlapping joints
The Siglin invention uses nuts and bolts as joining fasteners. Nuts and bolts rust tight, making the Siglin dike un-repairable in the best of working conditions. Stainless steel or brass nuts and bolts may reduce the seizing problems at great expense. However, under arctic conditions, the normally simple chore of starting a nut on a bolt, then tightening with a pair of wrenches is a very difficult task. Loosening and removing nuts and bolts which may be frozen in place with ice is also more difficult than expected. Nuts and bolts and wrenches are awkward to handle with arctic gloves and are likely to be dropped, leaving a litter.
The present invention has no nuts and bolts.
The Siglin dike uses posts set in concrete to support the wall sections. Concrete does not set well in freezing conditions. Thus, the Siglin dike cannot be installed in winter in many parts of the world, especially in permafrost zones.
The present invention does not rely on concrete. Furthermore, the present invention can utilize arctic cold to make an “ice mortar” or “ice-crete” of ice, frozen mud, or the like, for holding the structure in place.